Building a dynamic quiz application in ASP.net MVC

The quiz application I have build works just like that of W3Schools I got the inspiration from here and I wanted to understand more on asp.net MVC scafolding and Entity framework Code first. I set on my journey to write the application. Here is how it should work.

• The user goes to the quiz page to take the quiz
• The quiz has a question and a list of answers choices to choose from.
• When the user clicks on the next button , a new question is loaded dynamically.
• When the questions are completed the user is sent to a page showing his or her results.

Some ASP.Net MVC stuff

I used code first method by making poco classes and scaffolded all my controllers and i got all my CRUD methods an views for the controllers I choosed. Asp.net MVC Entity framework now the default database object relational mapper for the framework.To know more about Code first and the new scaffolding in Asp.net MVC check out this link.Scaffolding and Entity framework code first The next thing for me was to decide of what real life objects can be used and how they are connected.In this case

• I will need a to represent the question, the answer, and the answer choices.
• I needed one object to bring all these other object together and that is the Quiz object .
• I needed another object to manage the quiz since I decided to store the users answers in the memory.

Here are the classes and the ASP.net MVC will build the database using EF code first based on certain conventions you have to follow for it to be right .(Check out the tutorial link above)

To manage the quiz I use the Singleton pattern .The is only one quiz in the memory when you start until you finish. The quiz manager manages all events related to the quiz in the memory .I did not want to use the session object because wanted an optimal and a modular solution for the manager. Here is the code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using MyQuiz.Abstract;

namespace MyQuiz.Models
{
    public class QuizManager
    {
        static QuizManager instance;
        private QuizContext db = new QuizContext();
        int questionId = 1;
        public bool IsComplete = false;
        public Quiz quiz;

        private QuizManager()
        {            
            quiz = new Quiz();
            quiz.StartTime = DateTime.Now;
            quiz.QuizId = 1;
            quiz.Score = 0 ;
        }

        public static QuizManager Instance
        {
            get
            {
                if (instance == null)
                    instance = new QuizManager();
                return instance;
            }
        }

        public Question LoadQuiz()
        {
            var question = db.Questions.Find(questionId);
            return question;
        }

        public void SaveAnswer(string answers)
        {
            var question = db.Questions.Include("Answers").Where(x => x.QuestionId == questionId).Single();
            if (question.Answers.AnswerText == answers)
             quiz.Score++;
        }

        public bool MoveToNextQuestion()
        {
            bool canMove = false;

            if ( db.Questions.Count() > questionId)
            {
                questionId++;
                canMove = true;
            }

            return canMove;
        }

        public bool PreviosQuestion()
        {
            bool canMove = false;

            if (questionId > 1)
            {
                questionId--;
                canMove = true;
            }

            return canMove;
        }     
    }
}

The home controller that sends the quiz to the view was implemented this way

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using MyQuiz.Models;

namespace MyQuiz.Controllers
{
    public class HomeController : Controller
    {   

        public ActionResult Index()
        {   
            var question = QuizManager.Instance.LoadQuiz();
            return View(question);
        }
        [HttpPost]
        public ActionResult Index(string answer, int questionId)
        {   
            if(QuizManager.Instance.IsComplete) // Prevent score increase when quix has been completed
             return RedirectToAction("ShowResults");     
          
            QuizManager.Instance.SaveAnswer(answer);
            if (QuizManager.Instance.MoveToNextQuestion())
            {
                var question = QuizManager.Instance.LoadQuiz();
                return View(question);
            }
            QuizManager.Instance.IsComplete = true;
            return RedirectToAction("ShowResults");  
        }
        public ActionResult About()
        {
            return View();
        }
        public ActionResult ShowResults()
        {
            return View(QuizManager.Instance.quiz);
        }
    }
}

The View of the quiz . I use the JQuery live(---) function that allows for asynchronous loading and event handling on the page . After getting the response from the controller I simply replace the quiz div area with new questions using the replaceWith(---) function in JQuery. The process continuous until the user answers the last question .

@model MyQuiz.Models.Question
@{
    ViewBag.Title = "Index";
}


@using (Html.BeginForm("Index", "Home"))
    {
        


@Model.QuestionText
@Html.HiddenFor(x => x.QuestionId)

        




            @foreach (var choice in Model.AnswerChoices)
            {
                

                    @Html.RadioButton("answer", @choice.Choices) @choice.Choices
                
}
        

 
    }

The result page just displays the results of the quiz .Here is the source

@model MyQuiz.Models.Quiz

@{
    ViewBag.Title = "ShowResults";
}


ShowResults

Your total score is @Model.Score

Here is a screen shot of the final application

• There is more to add like scaffolding repositories.
• Use Dependency injection to reduce coupling of objects

Here is the source code if want to play with it. I moved the source code to Github since some readers could not access the source code on google drive. I took advantage to play with the new Github for windows which I find intresting since i have always used Apache Subversion, svn.
I have made some improvement on the code like moving it to MVC4  and  you can see the final application running here  MVC Quiz Application on  AppHarbor (I love these guys)
Happy programming !